Newbie question for purchasing seasonal rental

[Matheau Julien]

Hi BP forum!

Wanted some feedback from more experienced investors. I am looking at a turnkey property in coastal WA (Ocean Shores), approx 1 yr old, 2 bed 2 bath with garage, $440,000. It is in excellent condition and nicely maintained and landscaped. Renting there is seasonal. I am estimating $2500/mo vs $3500/mo. Maybe closer to $4000/mo during the peak. Minimal HOA.
Assuming that rent, 20% down payment, 50% vacancy rate, the cash flow would not be super, but one of the main reasons for my interest in real estate in the immediate present is the effect in reducing our taxable income, rather than for providing replacement income. With this in mind, I am thinking that the less-than-stellar cash on cash ROI might not be as important as long term benefits.
And would a bigger down payment be advantageous or a detriment, since the lower monthly mortgage payment would come at the cost of tying up capital that could be invested elsewhere?
There are certainly important issues we are overlooking, and I would love to hear your thoughts.

Thanks!